1. Field of the Invention
This invention relates to a plastic-made sanitary container capable of stably storing a medicine such as a vaccine, antibiotic, vitamin or amino acid, a nutrient solution, a transfusion solution, a cosmetic, a food such as a seasoning agent, or the like over a long period of time while maintaining cleanliness.
2. Description of the Related Art
Medicines, foods, cosmetics and other sanitary products have conventionally been stored in sanitary containers in many instances. Such sanitary containers must be able to protect their contents from intrusion of microorganisms and also to prevent their contents from a quality change, deterioration or the like by ultraviolet rays or the like.
The intrusion of microorganisms into a container is prevented by sealing the container or hermetically closing the container with a rubber plug or the like, whereas the quality change, deterioration or the like of a content by ultraviolet rays or the like is avoided by adding a deterioration preventive to the content or adding an ultraviolet absorber to a sanitary container itself.
Incidentally, glass-made containers have conventionally been used for many years as containers most suited from viewpoint of sanitation for medicines, nutrient solutions, transfusion solutions, foods and the like.
Glass-made containers are often made of soda-lime glass (soft glass), because soda-lime glass as a raw material for the glass-made containers permits easy melting and molding, has chemical durability and is of low price. A container made of soft glass may however undergo a quality or property change at a glass surface thereof by moisture in the surrounding atmosphere or by a solution contained therein. Described specifically, the glass may be hydrolyzed with water so that an alkali (Na.sup.+) may be dissolved out into the solution contained in the container or tiny chips called "flakes" may be formed.
Upon use of a glass-made container as a container for a sanitary product such as a medicine, the glass-made container may be subjected at an inner wall there-of to bloom treatment that the inner wall is treated with sulfur, sulfurous acid gas, ammonium sulfate or the like to eliminate alkalis, or a pH-regulating buffer, a quality or property change preventive or the like may be added to the content.
On the other hand, a container made of borosilicate glass (hard glass) undergoes alkali dissolution or flake formation, such as that mentioned above, less compared with a container made of soft glass. Hard glass is therefore most suited for the production of containers (ampoules) for injectable preparations, which containers (ampoules) require higher chemical durability. If the temperature or time is inadequate upon processing such as production of a container, hard glass may also become non-uniform in its glass structure so that an alkali may be dissolved out from an inner wall of the container or flakes may be formed from the inner wall of the container. To cope with this potential problem, surface treatment such as bloom treatment or fluoride treatment may be applied to the inner wall of the container, or silica coating or the like may be performed by coating SiO.sub.2 on the inner wall of the container by a CVD process or the like to form a coating of SiO.sub.2 there.
If a medicine, food or the like in a glass-made container is inferior in light resistance (ultraviolet light resistance), the transparency as a merit of the glass-made container conversely acts as a demerit. Iron-manganese compound or the like is therefore added to glass so that the glass-made container is used as a colored, light-shielding glass-made container. In this case, however, there is a potential problem that these metals may mix in the content such as the medicine or food.
In addition to the above-described problem of dissolution-out of alkalis on glass-made containers, there is another potential problem that may arise upon opening glass-made ampoules. Recent ampoules include an increasing number of ampoules which like ampoules of the easy-cut type, can be easily opened without using any special tool. It has however been pointed out that like conventional ampoules, such recent ampoules also become dangerous due to formation of sharp edges at cut faces and upon being cut, they form glass chips having a potential danger when mixed in medicine solutions. A glass-made container may have a still further problem that depending on the kind of a-medicine, the glass-made container may adsorb thereon the medicine in a greater amount than a plastic-made container.
Concerning the quality of glass upon its use as a material for medicine containers, various standard values are specified from the standpoints of safety and sanitation under the "Testing Method for Glass Containers for Injectable Preparations" in The Pharmacopoeia of Japan (thirteenth edition) (hereinafter, abbreviated as "JP13") and also in the United States Pharmacopeia XXIII (hereinafter abbreviated as "USP"), the British Pharmacopoeia (hereinafter abbreviated as "BP"), and the like.
To avoid such problems, there is now an increasing tendency to adopt plastic-made containers in place of glass-made containers. As official standards for plastic-made containers, there are standards for polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC) as specified in the eighth edition of the Pharmacopoeia of Japan (1971). Further, testing methods for plastic containers for transfusion solutions are also specified in the USP 17, the BS, the Pharmacopoeia of France, the Pharmacopoeia of Switzerland, Deutsche Industrie Norm (DIN--German Industrial Standards) (DIN58365), etc. They are also specified in Notification No. 370 of the Ministry of Health and Welfare issued under the Food Sanitation Law, Notification No. 20 of the same Ministry issued under the same Law (February, 1982), and the Food Additive Support F of U.S. Food and Drug Administration (FDA).
Plastics have an advantage over glass in that the former are lighter in weight than the latter. On the other hand, plastics are accompanied by disadvantages such that depending on the kinds of the plastics, they have poor moldability or formability and/or can provide only molded or otherwise formed products having insufficient strength and/or inferior gas transmission resistance and/or water vapor transmission resistance. Moreover, plastics are also inferior in ultraviolet ray transmission resistance (ultraviolet ray shielding property) to glass. It was therefore the situation that no plastics equipped in a well-balanced manner with properties required for sanitary containers had been found yet [see Japanese Patent Application Laid-Open (Kokai) No. HEI 5-293159].
Incidentally, concerning the light-shielding property (ultraviolet ray transmission resistance) of a colored container, the "Testing Method for Glass Containers for Injectable Preparations" in The Pharmacopoeia of Japan (thirteenth edition) specifies that the transmission rate should be 50% or lower at wavelengths of from 290 to 450 nm and 60% or higher (45% or higher in the case of a container having a wall thickness of 1.0 mm or greater) at wavelengths of form 590 to 610 nm. On the other hand, it is also specified in the USP that the transmission rate of a plastic-made container should be 15% or lower at wavelengths of from 290 to 450 nm.
Under the foregoing situation, the present applicant found that a cyclic olefin polymer is suited as a plastic for sanitary containers, and already filed a patent application thereon.
However, the cyclic olefin polymer is also poor in ultraviolet ray transmission resistance (ultraviolet let shielding property) like conventional plastics, and sanitary containers made of the cyclic olefin polymer have a potential problem that their contents may be changed or deteriorated in quality by such rays.